The Great Migration, also known as the Great Northward Migration or the Black Migration, was the movement of 6 million African Americans out of the rural Southern United States to the urban Northeast, Midwest, and West between 1910 and 1970). The migration was caused primarily by poor economic conditions for African Americans, as well as prevalent racial segregation and discrimination in the Southern states where Jim Crow laws were upheld). The Great Migration was one of the largest and most rapid mass internal movements in history, and in sheer numbers, it outranks the migration of any other ethnic group to the United States).

Some historians differentiate between a first Great Migration (1910–40), which saw about 1.6 million people move from mostly rural areas in the South to northern industrial cities, and a Second Great Migration (1940–70), which began after the Great Depression and brought at least five million people—including many townspeople with urban skills—to the North and West). During the Second Great Migration, more people moved North and further west to Californias major cities including Oakland, Los Angeles, and San Francisco, as well as Portland, Oregon and Seattle, Washington.

The Great Migration was key to the struggles and accomplishments of the long civil rights movement, as Black Americans became increasingly part of the big cities of all regions and in those urban settings steadily gained political and cultural influence. The people who migrated would become the forebears of most African-Americans born in the North and West. The Great Migration exposed the racial divisions and disparities that in many ways continue to plague the nation and dominate headlines today, from police killings of unarmed African-Americans to mass incarceration to widely documented biases in employment, housing, health care, and education.